chr20-10412723-A-G

Variant names:

• chr20-10412723-A-G
• rs74315397
• NM_170784.3:c.792T>C

Variant summary

Our verdict is Likely benign. The variant received -5 ACMG points: 2P and 7B. PM2 BP4_Strong BP6_Moderate BP7

The NM_018848.3(MKKS):​c.792T>C​(p.Tyr264Tyr) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000595 in 1,614,062 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Likely benign (★).

• Frequency:
  • Genomes: 𝑓 0.000053 (0 hom., cov: 32)
  • Exomes 𝑓: 0.000060 (0 hom.)
• Consequence: MKKS NM_018848.3 synonymous
• Clinical Significance: Likely benign criteria provided, single submitter B:2
• Conservation: PhyloP100: -3.38
• Publications: 3 publications found

Genes affected

MKKS (HGNC:7108): (MKKS centrosomal shuttling protein) This gene encodes a protein which shares sequence similarity with other members of the type II chaperonin family. The encoded protein is a centrosome-shuttling protein and plays an important role in cytokinesis. This protein also interacts with other type II chaperonin members to form a complex known as the BBSome, which involves ciliary membrane biogenesis. This protein is encoded by a downstream open reading frame (dORF). Several upstream open reading frames (uORFs) have been identified, which repress the translation of the dORF, and two of which can encode small mitochondrial membrane proteins. Mutations in this gene have been observed in patients with Bardet-Biedl syndrome type 6, also known as McKusick-Kaufman syndrome. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Feb 2023]

MKKS Gene-Disease associations (from GenCC):

• McKusick-Kaufman syndrome

  Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), G2P, Orphanet
• Bardet-Biedl syndrome 6

  Inheritance: AR Classification: STRONG Submitted by: Genomics England PanelApp, Labcorp Genetics (formerly Invitae)
• Bardet-Biedl syndrome

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Likely_benign. The variant received -5 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.9).
• BP6: Variant 20-10412723-A-G is Benign according to our data. Variant chr20-10412723-A-G is described in ClinVar as Likely_benign. ClinVar VariationId is 1110126.Status of the report is criteria_provided_single_submitter, 1 stars.
• BP7: Synonymous conserved (PhyloP=-3.38 with no splicing effect.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_018848.3. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	MKKS	NM_170784.3	MANE Select	c.792T>C	p.Tyr264Tyr	synonymous	Exon 3 of 6	NP_740754.1
	MKKS	NM_018848.3		c.792T>C	p.Tyr264Tyr	synonymous	Exon 3 of 6	NP_061336.1
	MKKS	NR_072977.2		n.347-3920T>C		intron	N/A

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	MKKS	ENST00000347364.7	TSL:1 MANE Select	c.792T>C	p.Tyr264Tyr	synonymous	Exon 3 of 6	ENSP00000246062.4
	MKKS	ENST00000399054.6	TSL:1	c.792T>C	p.Tyr264Tyr	synonymous	Exon 3 of 6	ENSP00000382008.2
	MKKS	ENST00000651692.1		c.792T>C	p.Tyr264Tyr	synonymous	Exon 4 of 7	ENSP00000498849.1

Frequencies

GnomAD3 genomes AF: 0.0000526 AC: 8 AN: 152200 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.0000241

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.0000654

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000882

Gnomad OTH AF: 0.00

GnomAD2 exomes AF: 0.0000398 AC: 10 AN: 251068 AF XY: 0.0000442

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000882

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000602 AC: 88 AN: 1461862 Hom.: 0 Cov.: 33 AF XY: 0.0000550 AC XY: 40 AN XY: 727232

African (AFR) AF: 0.00 AC: 0 AN: 33480

American (AMR) AF: 0.00 AC: 0 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26134

East Asian (EAS) AF: 0.00 AC: 0 AN: 39694

South Asian (SAS) AF: 0.00 AC: 0 AN: 86258

European-Finnish (FIN) AF: 0.0000374 AC: 2 AN: 53414

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 0.0000737 AC: 82 AN: 1111998

Other (OTH) AF: 0.0000662 AC: 4 AN: 60392

GnomAD4 genome AF: 0.0000526 AC: 8 AN: 152200 Hom.: 0 Cov.: 32 AF XY: 0.0000134 AC XY: 1 AN XY: 74366

African (AFR) AF: 0.0000241 AC: 1 AN: 41444

American (AMR) AF: 0.0000654 AC: 1 AN: 15286

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3468

East Asian (EAS) AF: 0.00 AC: 0 AN: 5198

South Asian (SAS) AF: 0.00 AC: 0 AN: 4832

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10622

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 316

European-Non Finnish (NFE) AF: 0.0000882 AC: 6 AN: 68028

Other (OTH) AF: 0.00 AC: 0 AN: 2094

Alfa AF: 0.0000659 Hom.: 0

Bravo AF: 0.0000529

EpiCase AF: 0.0000545

EpiControl AF: 0.0000593

ClinVar

ClinVar submissions as Germline

Significance: Likely benign

Revision: criteria provided, single submitter

Pathogenic	VUS	Benign	Condition
-	-	1	Bardet-Biedl syndrome;C0948368:McKusick-Kaufman syndrome (1)
-	-	1	MKKS-related disorder (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.90
CADD	Benign	0.023
DANN	Benign	0.48
PhyloP100		-3.4

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.0		Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Other links and lift over

dbSNP: rs74315397; hg19: chr20-10393371;